Adds a sane example of how one might setup the cache-control headers when using fastify-static to host a site, in particular a site built with vite.js

I've been burnt by this recently and I thought it could help others if it was front and center in the docs. In particular, looking at the existing examples, one might think that setting cacheControl: false will disable caching when in fact it will simply disable setting the header and let the browser to it's default caching (which is rarely the desired outcome).

related to #508 & #477

Not sure if this merits an example front in center in the readme, but it would have saved me some headache in some personal projects.

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct